The present invention is generally in the field of digital printing systems. More specifically, the present invention relates to a system and method useful for ink-jet printing onto substrates. The present invention is directed to ink-jet printing onto textiles and other materials printed in an industrial environment using spot color, process color and hybrid color printing modes.
Textiles having a printed pattern thereon are used in many different items. Clothing, fabrics for furniture upholstery, automotive upholstery, window treatments, and bedroom furnishings, such as bedspreads, sheets and pillow cases, are just a few of the uses for these textiles. In addition to textiles, other materials have used printed patterns, such as wall coverings, floor coverings and signage. These patterns on the printed textiles and other materials may include many different colors, several of which may be very vivid and striking.
Typically, these printed textiles are produced using standard printing presses. After determining the colors to be used, screens or other mechanical forms are made for each color and these mechanical forms are placed in the press. Next, a fabric is placed on the press and colorants are added to the press. The press then applies the colorants onto the fabric via the mechanical forms to produce the desired pattern.
Generally, the fixed costs for preparing the screens or other mechanical forms and setting up the presses are spread over long production runs for the textile or other material being printed and are, therefore, very reasonable on a per yard basis. Therefore, the technology used to make these printed textiles has changed very little over the years. However, these fixed costs can be very high. If only small quantities of the printed textile or other material are produced, the cost per yard produced can be very expensive. However, smaller quantities are needed when producing a variety of different colored samples and patterns to help with market assessment of the desired pattern. Since not all designed patterns are accepted by the market, print producers have had an aversion to preparing pre-production samples of very many patterns. Additionally, the time needed to change from one colored pattern to another is extensive.
Therefore, there is a need for a system and process which is capable of producing printed textiles which significantly reduces the fixed costs and preparation time, thereby allowing a plurality of samples to be produced in an inexpensive manner and to be produced on a just-in-time basis.
Digital color printing is one possible alternative for low cost production of textile samples. Digital color printing of documents has been known for some time. Digital color printers, including ink-jet printing systems, are widely used in many different fields to produce documents and presentations having the added benefit of color. However, due to the limited number of color cartridges that may be used in a digital printer, typically four to eight, current printers are limited in the colors they can recreate. To enhance the number of printable colors, current digital color printers use a xe2x80x9cprocess colorxe2x80x9d method when printing to expand upon the colors in the color cartridges.
In a xe2x80x9cprocess colorxe2x80x9d method, the digital color printer uses xe2x80x9cprocess colors,xe2x80x9d in which either three (cyan, magenta and yellow) or four (plus black) primary ink colors which comprise a process color set. These primary ink colors are commonly referred to by their initials C, M, Y and K, respectively. In addition, other process color sets, such as (C, M, Y, K, green, and orange) or (C, M, Y, K, light cyan, and light magenta), are known in the art. Generally, the process colors in a process color set are used to produce a wide range of printed colors by combining various amounts of each of the process colors in the form of adjacent or superimposed dots. C, M and Y are subtractive primary ink colors and may be combined to form most other ink colors.
Spot color printing involves application of solid areas of pre-mixed ink rather than overlapping multiple inks (C, M, Y and K) to create colors. For example, the deposition of an ink having the pre-mixed color of IBM(copyright) blue onto a substrate would be a spot color process.
The range of possible colors that may be printed by a printing process is referred to as the xe2x80x9cgamutxe2x80x9d of the process. Unfortunately, the gamut of most printing processes is much smaller than the total range of colors that can be seen. Specifically, the gamut of process color printers is smaller than the possible gamuts produced by traditional printing presses, such as offset, flexographic, gravure and screen printing presses, which print with pre-mixed or xe2x80x9cspotxe2x80x9d color inks. In other words, ink-jet printing systems relying on process color techniques cannot produce colors that match exactly many of the desired colors (i.e., IBM(copyright) blue, Coca-Cola(copyright) red or colors designed by fashion designers and produced by specific textiles dyes or pigments) one sees in everyday life. Therefore, ink-jet printing systems are not able to reproduce many of the vivid and striking colors currently seen on most textile patterns. As various industries, such as the textile industry, begin to transition from traditional press technology to digital printing technology, the restricted color gamut of process color devices will dampen the rate of adoption of digital printing.
Therefore, what is needed is a combination of spot color printing with digital printing which will provide the same color gamut expected by the users of traditional presses as well the benefits that are inherent to digital printing, such as short run printing, just-in-time production, and distributed printing, among others.
The present invention provides a system and method for digital printing which is useful for ink-jet printing onto various substrates. Even more specifically, the present invention is directed to ink-jet printing onto textiles using a spot color printing mode, a process color printing mode, and/or a hybrid of both spot and process color printing modes. The present invention uses standard colorants, including textile dyes and pigments, thereby allowing the system to be used in existing manufacturing plants. As used herein, the term xe2x80x9cdyexe2x80x9d is meant to include all dyes and pigments. Next, the present invention includes methods of formulating ink-jet inks wherein these dyes are purified using a system specifically designed to selectively remove unwanted impurities, such as particulates, dissolved molecules, and ions, from the dyes and to formulate these dyes into inks capable of being used in an ink-jet printing process.
After the dyes have been purified, they are placed into and shipped in specially designed containers to a color kitchen, which may be located at the manufacturing plant. The containers are designed to not only prevent impurities, including air, from entering the container and to prevent expiration of water from within, but also such that they may be easily connected to the color kitchen. The color kitchen is designed to mix the purified dye stock solutions with water and optionally other additives to form the inks needed to reproduce a particular color, i.e., a spot color. The determination of the colors to be used is performed using a recipe creation software which analyzes the colors to be printed and selects which formulations of dyes should be mixed together to form the colors needed to reproduce the selected colors in the pattern to be printed. Next, the color kitchen dispenses the appropriate purified dye stock solutions, generates the selected ink-jet ink formulations into specially designed containers or ink jet cartridges. These containers are preferably designed to include a removable connector that allows the color kitchen to dispense the purified dye stock solutions, water and additives into the container. The same connector, when attached to these containers allows the container to be used directly in an ink-jet printing system. Additionally, the containers are preferably designed to ensure that no impurities are able to get into the dispensed inks and therefore clog the ink-jet printing system nozzles or destabilize the inks.
In general, because ink-jet printing systems currently print with no more than 6 to 8 colors, and because many printed textiles have patterns containing more than eight colors, the present invention also includes a hybrid color management software which directs the printer to use a spot color process to exactly reproduce some colors of the desired pattern while using a process color process to reproduce the remaining, less important colors of the pattern, thereby allowing the reproduction of a printed textile using a digital printing process.
Therefore, the present invention is capable of digitally printing a pattern onto a substrate using standard printing dyes. The present invention also provides a filtration system which is capable of purifying standard printing dyes into stable solutions that can be used in a color kitchen. Additionally, the present invention includes containers which are designed to transport purified dyes solutions or pigment dispersions to a color kitchen without impurities entering the container while also permitting the dyes to be introduced into the color kitchen. The present invention provides a color kitchen which mixes the purified dye solutions into the necessary colors as determined using a recipe creation software program. Additionally, the present invention provides a second container which is adaptable to fit onto the color kitchen while also being adaptable to fit onto an ink-jet printing system. Finally, the present invention is capable of using both a spot color printing mode and a process color printing mode to reproduce a desired printed pattern on a textile and digitally printing that pattern onto a textile to produce more pattern colors than there are ink colors on the printing system.
These and other features and advantages of the present invention will become apparent after a review of the following detailed description of the invention.